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US5701065A
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US
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Method and apparatus for controlling synchronous motor
Assignee: Individual
•
Filing: 1996-01-11
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Granted: 1997-12-23
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Expires: 2016-01-11
Abstract
Abstract In a novel method and apparatus for controlling a synchronous motor, an angular position transducer, in whose output winding three-phase voltages with amplitude variations of N (N: an integer of 1 or more) cycles per revolution is induced, is directly coupled to a synchronous motor with 2N poles so that the demodulated a-phase voltage of the transducer has its positive peak value multiplied by the cosine of a selected angle as MMF phase angle when a direct axis of the motor is located in the position of its a-phase winding axis. The instructions to control three-phase currents of an inverter feeding the motor are produced by multiplying the current phase instructions by the amplitude instruction. The former is directly obtained using the three-phase voltages demodulated from the output of the transducer and the latter is derived from the detected speed deviation or torque instruction. A changeover device is used for the current phase instruction to produce the reverse torque necessary in the four-quadrant drive of synchronous reluctance motors and interior permanent magnet synchronous motors. Although the latter is the same as the conventional method, the former simplifies the apparatus because of analog processing not using expensive R/D converters. Therefore, the present invention is effective to reduce costs and to increase reliability of the control apparatus synchronous motors.
Inventors
- 👤 Akira Ishizaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:06
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/022; H02P25/03; H02P21/00
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
198 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed and rotating direction and for determining a speed deviation which is the difference between the actual speed and a target speed; a PI controller for providing a current amplitude instruction signal based on the speed deviation; and three multipliers for respectively multiplying the voltage output by the PI controller by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter.
Claim 2
Independent Claim
198 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed and rotating direction and for determining a speed deviation which is the difference between the actual speed and a target speed; a PI controller for providing a current amplitude instruction signal based on the speed deviation; and three multipliers for respectively multiplying the voltage output by the PI controller by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter.
Claim 3
Dependent Claim
40 words
An apparatus as recited in claim 1, further comprising a phase changeover circuit disposed between the demodulator and the three multipliers for producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator.
Claim 4
Dependent Claim
21 words
An apparatus as recited in claim 2, further comprising phase shifters disposed between the phase changeover circuit and the three multipliers.
Claim 5
Dependent Claim
19 words
An apparatus as recited in claim 1, further comprising phase shifters disposed between the demodulator and the three multipliers.
Claim 6
Dependent Claim
22 words
An apparatus as recited in claim 2, further comprising an absolute value circuit disposed between the PI controller and the three multipliers.
Claim 7
Dependent Claim
22 words
An apparatus as recited in claim 3, further comprising an absolute value circuit disposed between the PI controller and the three multipliers.
Claim 8
Independent Claim
232 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which two of three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the two of three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed and for determining a speed deviation which is the difference between the actual speed and a target speed; a PI controller for providing a current amplitude instruction signal based on the speed deviation; two multipliers for respectively multiplying the voltage output by the PI controller by the two of three-phase output voltages of the demodulator for generating two of three-phase current instructions for inputting to a current control circuit of the inverter; and an adder for adding the outputs of the two multipliers to generate a third of the three-phase current instructions for inputting to the current control circuit of the inverter.
Claim 9
Independent Claim
232 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which two of three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the two of three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed and for determining a speed deviation which is the difference between the actual speed and a target speed; a PI controller for providing a current amplitude instruction signal based on the speed deviation; two multipliers for respectively multiplying the voltage output by the PI controller by the two of three-phase output voltages of the demodulator for generating two of three-phase current instructions for inputting to a current control circuit of the inverter; and an adder for adding the outputs of the two multipliers to generate a third of the three-phase current instructions for inputting to the current control circuit of the inverter.
Claim 10
Independent Claim
195 words
A method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed and rotating direction and determining a speed deviation which is the difference between the actual speed and a target speed with a speed detector; providing a current amplitude instruction signal based on the speed deviation with a PI controller; and respectively multiplying the voltage output by the PI controller by the three-phase output voltage of the demodulator and generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 11
Independent Claim
195 words
A method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed and rotating direction and determining a speed deviation which is the difference between the actual speed and a target speed with a speed detector; providing a current amplitude instruction signal based on the speed deviation with a PI controller; and respectively multiplying the voltage output by the PI controller by the three-phase output voltage of the demodulator and generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 12
Dependent Claim
40 words
A method as recited in claim 8, further comprising producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator using a phase changeover circuit disposed between the demodulator and the three multipliers.
Claim 13
Dependent Claim
33 words
A method as recited in claim 9, further comprising shifting the phase of the output of the phase changeover circuit using phase shifters disposed between the phase changeover circuit and the three multipliers.
Claim 14
Dependent Claim
29 words
A method as recited in claim 8, further comprising shifting the phase of the output of the demodulator using phase shifters disposed between the demodulator and the three multipliers.
Claim 15
Dependent Claim
34 words
A method as recited in claim 9, further comprising taking an absolute value of an output from the PI controller using an absolute value circuit disposed between the PI controller and the three multipliers.
Claim 16
Dependent Claim
34 words
A method as recited in claim 10, further comprising taking an absolute value of an output from the PI controller using an absolute value circuit disposed between the PI controller and the three multipliers.
Claim 17
Independent Claim
230 words
A method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in two of three output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the two of three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed and determining a speed deviation which is the difference between the actual speed and a target speed with a speed detector; providing a current amplitude instruction signal based on the speed deviation with a PI controller; respectively multiplying the voltage output by the PI controller by the two of three-phase output voltage of the demodulator and generating two of three-phase current instructions for inputting to a current control circuit of the inverter using two multipliers; and adding the outputs of the two multipliers to generate a third of the three-phase current instructions for inputting to the current control circuit of the inverter using an adder.
Claim 18
Independent Claim
230 words
A method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in two of three output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the two of three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed and determining a speed deviation which is the difference between the actual speed and a target speed with a speed detector; providing a current amplitude instruction signal based on the speed deviation with a PI controller; respectively multiplying the voltage output by the PI controller by the two of three-phase output voltage of the demodulator and generating two of three-phase current instructions for inputting to a current control circuit of the inverter using two multipliers; and adding the outputs of the two multipliers to generate a third of the three-phase current instructions for inputting to the current control circuit of the inverter using an adder.
Claim 19
Independent Claim
182 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed for display or system control; a calculating circuit for providing a current amplitude instruction signal based on a given torque instruction; three multipliers for respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter.
Claim 20
Independent Claim
182 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed for display or system control; a calculating circuit for providing a current amplitude instruction signal based on a given torque instruction; three multipliers for respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter.
Claim 21
Dependent Claim
40 words
An apparatus as recited in claim 15, further comprising a phase changeover circuit disposed between the demodulator and the three multipliers for producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator.
Claim 22
Dependent Claim
17 words
An apparatus as recited claim 15, further comprising phase shifters disposed between the demodulator and three multipliers.
Claim 23
Dependent Claim
20 words
An apparatus as recited claim 16, further comprising phase shifters disposed between the phase changeover circuit and the three multipliers.
Claim 24
Independent Claim
214 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output in which windings three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed for display or system control; an electrical circuit for providing a current amplitude instruction signal corresponding to a position of a mechanical operational part; a circuit for giving a positive or negative sign for the current amplitude instruction signal corresponding to a forward or reverse direction of torque given as an instruction; three multipliers for respectively multiply the output voltage from the calculating circuit by the three, phase output voltage of the demodulator for generating three-phase current instruction for inputting to a current control circuit of the inverter.
Claim 25
Independent Claim
214 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output in which windings three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a speed detector for determining an actual speed for display or system control; an electrical circuit for providing a current amplitude instruction signal corresponding to a position of a mechanical operational part; a circuit for giving a positive or negative sign for the current amplitude instruction signal corresponding to a forward or reverse direction of torque given as an instruction; three multipliers for respectively multiply the output voltage from the calculating circuit by the three, phase output voltage of the demodulator for generating three-phase current instruction for inputting to a current control circuit of the inverter.
Claim 26
Dependent Claim
17 words
An apparatus as recited claim 19, further comprising phase shifters disposed between the demodulator and three multipliers.
Claim 27
Independent Claim
237 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a phase changeover circuit disposed between the demodulator and three multipliers for producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator; a speed detector for determining an actual speed for display or system control; an electrical circuit for providing a current amplitude instruction signing corresponding to a position of a mechanical operational part; a circuit for providing a positive or negative voltage corresponding to a forward or reverse direction of torque given as an instruction; three multipliers for respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter.
Claim 28
Independent Claim
237 words
An apparatus for controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: an angular position transducer including output windings in which three-phase voltages with amplitude variations of N cycles per revolution are induced, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; an inverter for outputting three-phase currents for feeding the motor; a demodulator for demodulating the three-phase output voltages of the angular position transducer; a phase changeover circuit disposed between the demodulator and three multipliers for producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator; a speed detector for determining an actual speed for display or system control; an electrical circuit for providing a current amplitude instruction signing corresponding to a position of a mechanical operational part; a circuit for providing a positive or negative voltage corresponding to a forward or reverse direction of torque given as an instruction; three multipliers for respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter.
Claim 29
Dependent Claim
20 words
An apparatus as recited claim 21, further comprising phase shifters disposed between the phase changeover circuit and the three multipliers.
Claim 30
Independent Claim
180 words
An method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed with a speed detector for display or system control; providing a current amplitude instruction signal based on a given torque instruction with a calculating circuit; respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 31
Independent Claim
180 words
An method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed with a speed detector for display or system control; providing a current amplitude instruction signal based on a given torque instruction with a calculating circuit; respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 32
Dependent Claim
40 words
A method as recited in claim 23, further comprising producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator using a phase changeover circuit disposed between the demodulator and the three multipliers.
Claim 33
Dependent Claim
29 words
A method as recited in claim 23, further comprising shifting the phase of the output of the demodulator using phase shifters disposed between the demodulator and the three multipliers.
Claim 34
Dependent Claim
31 words
A method as recited in claim 24, further comprising shifting the phase of the output of the demodulator using phase shifters disposed between the phase changeover circuit and the three multipliers.
Claim 35
Independent Claim
209 words
An method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed with a speed detector for display or system control; providing a current amplitude instruction signal corresponding to the position of a mechanical operational part, with an electrical circuit; providing positive or negative sign for the current amplitude instruction signal corresponding to forward or reverse direction of torque given as an instruction with a circuit; respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 36
Independent Claim
209 words
An method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; determining an actual speed with a speed detector for display or system control; providing a current amplitude instruction signal corresponding to the position of a mechanical operational part, with an electrical circuit; providing positive or negative sign for the current amplitude instruction signal corresponding to forward or reverse direction of torque given as an instruction with a circuit; respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 37
Dependent Claim
29 words
A method as recited in claim 27, further comprising shifting the phase of the output of the demodulator using phase shifters disposed between the demodulator and the three multipliers.
Claim 38
Independent Claim
233 words
A method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator using a phase changeover circuit disposed between the demodulator and the three multipliers; determining an actual speed with a speed detector for display or system control; providing a current amplitude instruction signal corresponding to the position of a mechanical operational part; with an electrical circuit; providing a positive or negative voltage corresponding to a forward or reverse direction of torque given as an instruction; respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 39
Independent Claim
233 words
A method of controlling a synchronous motor having 2N poles, where N is an integer greater than or equal to one, comprising: inducing three-phase voltages with amplitude variations of N cycles per revolution in output windings of an angular position transducer, the angular position transducer being mechanically directly coupled to the motor so that a demodulated a-phase voltage of the transducer has its positive peak value multiplied by a cosine of a predetermined MMF phase angle when a direct axis of the motor is located in a position of its a-phase winding axis; outputting three-phase currents for feeding the motor from an inverter; demodulating the three-phase output voltages of the angular position transducer with a demodulator; producing a reverse torque in the motor by changing the phase of the three-phase output of the demodulator using a phase changeover circuit disposed between the demodulator and the three multipliers; determining an actual speed with a speed detector for display or system control; providing a current amplitude instruction signal corresponding to the position of a mechanical operational part; with an electrical circuit; providing a positive or negative voltage corresponding to a forward or reverse direction of torque given as an instruction; respectively multiplying the output voltage from the calculating circuit by the three-phase output voltages of the demodulator for generating three-phase current instructions for inputting to a current control circuit of the inverter using three multipliers.
Claim 40
Dependent Claim
31 words
A method as recited in claim 29, further comprising shifting the phase of the output of the demodulator using phase shifters disposed between the phase changeover circuit and the three muiltipliers.
References Cited (Backward Citations)
US3696277A
Cited
US4344023A
Cited
US4712050A
Cited
US4678973A
Cited
US5006768A
Cited
US5155419A
Cited
US5486743A
Cited
US5481166A
Cited
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